Abstract Over 70% of people with serious and persistent mental illnesses (SPMI) smoke cigarettes. We have found that delivery of the 5 As of smoking cessation (Ask, Advise, Assess, Assist, Arrange) to persons with SPMI, a practice required by the VA, produces modest reductions in smoking and some increased use of smoking cessation aids, but does not increase abstinence. Existing best practices for smoking cessation in SPMI produce low short-term abstinence rates and almost no sustained abstinence. A new approach is needed that is designed for persons with SPMI and utilizes all available strategies for addiction treatment. We have developed an intervention called Behavioral Treatment of Smoking Cessation in SPMI (BTSCS), an innovative program that supplements pharmacotherapy and education with contingency management and a multifaceted behavioral group treatment that addresses the cognitive, motivational, and social support problems characteristic of people with SPMI. We propose to conduct a randomized trial of BTSCS compared to a manualized standard cessation program (StSST) that reflects current best practices. BTSCS was modeled after a successful program (Behavioral Treatment of Substance Abuse in SPMI) created by the study team that was designed for people with dual disorders. Hypotheses: We hypothesize that BTSCS will be more effective than StSST in producing and sustaining abstinence as measured by self report and expired CO levels. Subject Population: We will recruit 210 people with SPMI who smoke at least 10 cigarettes per day from the VA Maryland Healthcare System. We expect to randomize 178 people. Procedures: Participants in both conditions will receive brief outreach. Research assessments will be completed at baseline, 3 months (end of treatment), and 3- and 6- month follow ups. Potential Impact on Veterans' Health Care: The VA has recognized the high medical, economic, and social costs of smoking with directives to ensure that veterans are offered cessation programs. Testing an innovative smoking cessation treatment for persons with SPMI is highly significant for the VA because: (1) the rates of smoking among veterans are higher that the general population; (2) smoking rates among persons with SPMI are higher still, and; (3) there are virtually no smoking cessation treatments for veterans with SPMI that are effective in producing abstinence.